When They Put Phosphorus Shells in Bazooka— Japanese Called it White Death

When They Put Phosphorus Shells in Bazooka— Japanese Called it White Death

March 17th, 1945. 5:47 hours, Iwo Jima. Staff Sergeant Robert “Dutch” Henderson, 23, pressed his back against the sulfur-stained volcanic rock. His M1 Garand, slick with sweat despite the morning chill. 300 yards ahead, through the acrid smoke drifting across the black sand terraces, he could see them. Concrete pillboxes the Navy said they’d destroyed.

 Bunkers that aerial reconnaissance swore didn’t exist anymore. The 5th Marine Division had been assured this sector was clear. The Japanese gunfire said otherwise. Henderson glanced at the young Marine beside him, PFC James Morrison, barely 19, cradling something Henderson had never seen before. It looked like a standard M1A1 bazooka, but the rocket in Morrison’s trembling hands was different.

Instead of the familiar olive drab warhead, this one bore yellow and white markings and stenciled warnings Henderson couldn’t quite read in the dim light. Morrison had received it just hours earlier with instructions that made no sense. Point, shoot, and don’t look directly at the impact. The bunker ahead erupted again.

 Its machine gun tearing through two Marines who tried to advance. Henderson knew what was about to happen. They’d try conventional bazookas first. They always did. The shaped charges would punch into the concrete, detonate, and accomplish exactly nothing against the reinforced Japanese fortifications. Then more Marines would die trying to get close enough with satchel charges or flamethrowers.

Unless Morrison’s strange rocket worked the way the weapons sergeant had promised. “White flame,” the sergeant had said. “The Japs are calling it white flame.” By March 1945, the Pacific War had become a grim arithmetic problem that American commanders couldn’t solve with conventional mathematics. Every Japanese-held island brought the same nightmare.

Elaborate underground fortifications, interconnected tunnel systems, and defensive positions designed by engineers who understood that they were building tombs, not bunkers. The Japanese weren’t fighting to win anymore. They were fighting to extract the maximum American casualties, hoping to make the cost of invasion so terrible that the United States would negotiate peace rather than assault the home islands.

Iwo Jima represented this strategy’s most sophisticated implementation. The island’s commander, Lieutenant General Tadamichi Kuribayashi, had spent eight months transforming eight square miles of volcanic rock into a labyrinth of death. His engineers constructed 11 miles of tunnels, connecting 1,500 rooms, chambers, and fighting positions.

They built pillboxes with walls 5 ft thick, reinforced with steel rails from Manchurian mines. They positioned guns in caves with multiple firing ports, allowing defenders to shoot, retreat into the tunnels, and emerge elsewhere when counterattacked. Traditional American weapons failed against this defensive network.

The M1A1 bazooka, introduced in 1942, had proven effective against German tanks and fortifications in Europe. Its 2.36-in rocket could penetrate 4 in of armor plate at 300 yards. But penetration meant nothing against positions built from reinforced concrete and volcanic rock. The shaped charge would punch through the outer wall, explode inside a 5-ft thick fortification, and accomplish nothing except alerting the defenders to incoming infantry.

Artillery bombardment had consumed 22,000 rounds during the pre-invasion preparation, the most intense shore bombardment in Pacific War history. Navy spotters reported direct hits on bunkers, watched concrete structures collapse under 16-in naval shells, confirmed positions destroyed. Then the Marines landed and discovered the bunkers were fine.

The Japanese had built false structures to absorb bombardment while the real fortifications remained hidden underground, emerging through camouflaged firing ports only when American troops came within killing range. Flamethrowers worked, but flamethrower operators died. The effective range of the M2 flamethrower was 30 yards.

 To use it, Marines had to cross open ground under direct machine gun and mortar fire carrying 70 lb of jellied gasoline on their backs. On Iwo Jima’s first day alone, February 19th, 1945, the 5th Marine Division lost eight flamethrower operators in the first hour. Each one killed represented months of specialized training and experience that couldn’t be quickly replaced.

The casualty mathematics were unsustainable. Intelligence estimated 21,000 Japanese defenders on Iwo Jima. American planners projected 15,000 US casualties to secure the island, a projection based on previous island campaigns and already considered horrific. By March 17th, after 26 days of fighting, American casualties had reached 19,217, including 4,189 killed.

The Japanese had perfected reverse slope defense, interlocking fields of fire, and a bunker placement strategy that turned every American advance into a killing ground. Marine commanders needed a weapon that combined the bazooka’s range with the flamethrower’s effectiveness against fortifications. They needed something that could reach bunkers from cover, something that didn’t require a Marine to expose himself for 30 seconds while pouring fire into a gun port.

They needed to kill defenders inside positions that shaped charges couldn’t damage and conventional explosives couldn’t collapse. The Chemical Warfare Service had been working on the answer since 1943, but it had taken two years of combat experience to understand the question. If you want to see how American engineers turned one of chemistry’s most terrifying elements into a rocket-propelled nightmare that made Japanese defenders abandon positions they’d sworn to defend to the death, hit that subscribe button and turn on

notifications. These forgotten weapons changed the Pacific War, and the stories deserve to be remembered. Back to Sergeant Henderson. The M10 white phosphorus rocket for the 2.36-in bazooka represented chemical warfare packaged in a format the Geneva Protocol hadn’t anticipated. Officially designated the M10 WP round, unofficially called everything from Willie Peter to the Devil’s Sparkler.

This ammunition transformed a tank-hunting weapon into something that terrified entrenched defenders more than any conventional explosive. The rocket weighed 3.4 lb, slightly lighter than the standard M6A1 high explosive anti-tank round. Its warhead contained 1.3 lb of white phosphorus suspended in a bursting charge designed not to penetrate armor, but to scatter burning particles across the maximum possible area.

The designers had removed the shaped charge cone entirely, replacing it with a thin metal casing scored to fragment into hundreds of pieces upon detonation. White phosphorus ignites spontaneously when exposed to oxygen, burning at temperatures exceeding 5,000° F. Unlike thermite, which requires sustained contact to be effective, white phosphorus particles embed themselves in whatever they strike, flesh, wood, fabric, or equipment, and continue burning until either the oxygen supply is exhausted or the phosphorus is

completely consumed. Water doesn’t extinguish white phosphorus fires. Immersing a burning particle in water temporarily suppresses the reaction, but the phosphorus reignites the moment it returns to air. The M10’s bursting charge was calibrated to scatter phosphorus particles across a 40-ft radius. Upon impact, the rocket’s base detonating fuse triggered a small explosive that ruptured the warhead casing, releasing the phosphorus while simultaneously fragmenting the metal shell.

The burning phosphorus particles, each piece ranging from dust-sized specs to fragments the size of a dime, would spray into bunker firing ports, ventilation shafts, and tunnel entrances. Inside enclosed spaces, the particles consumed available oxygen while producing dense white smoke, hence the white flame [snorts] nickname Japanese defenders gave it.

The Chemical Warfare Service had tested various phosphorus delivery systems since 1943. Artillery shells worked, but lacked precision against point targets. Grenades were effective, but required close approach, negating the tactical advantage. The breakthrough came when weapons engineers realized the bazooka provided the perfect platform.

Man-portable, accurate to 300 yd, and already in widespread Marine Corps use, with operators trained in its employment. Development challenges focused on stability. White phosphorus reacts violently with moisture, and Pacific combat environments were perpetually humid. The solution involved hermetically sealing the phosphorus in a waterproof container within the warhead, then surrounding it with a buffer layer that prevented premature ignition from the rocket motor’s heat.

Each M10 round required careful storage in sealed tubes with desiccant packets, and gunners received strict warnings never to fire a rocket that showed any sign of corrosion or damage to the waterproof seal. The first production M10 rounds arrived in the Pacific Theater in January 1945, distributed to select Marine units with minimal explanation.

The rockets came with typewritten instruction sheets, warning operators about backblast safety, proper storage, and one emphatic note. Do not attempt to recover or handle unexploded rounds. Mark position and notify EOD personnel immediately. The warning existed because phosphorus particles could scatter even from impact-fused rounds that failed to detonate, creating invisible hazard zones that would ignite anyone who disturbed the contaminated soil.

Marines who first saw the M10 rounds recognized they weren’t standard ammunition immediately. The yellow and white hazard markings followed chemical warfare protocols, not conventional ordnance standards. The rockets came in special canisters with prominent warnings in multiple languages. Armorers, who’d been loading bazookas for years, approached the M10 with unusual caution, and rumors spread quickly.

This was something new, something the brass thought might change the ground war equation. Nobody really understood what white flame meant until they saw it work. Henderson watched Morrison fumble with the M10 round, trying to load it while keeping low behind the rock outcropping. The kid’s hands were shaking so badly, he nearly dropped the rocket twice.

Henderson reached over, steadied Morrison’s grip, helped guide the round into the launcher tube until the contact spring engaged with an audible click. “You ever fire one of these?” Henderson asked, already knowing the answer. Morrison shook his head. “Sergeant Barnes just handed it to me this morning. Said point it at the bunker and squeeze the trigger.

Said it would work different than regular rockets.” The bunker ahead had gone quiet again. The machine gun crew waiting for more Marines to expose themselves. Henderson had seen this pattern for 3 weeks now. The Japanese would fire disciplined bursts, conserve ammunition, and wait. They had ammunition. They had water.

They had fortifications that conventional weapons couldn’t breach. They had time. “Different how?” Henderson pressed. “Didn’t say, just said I’d know when I saw it.” 5:52 hours. The sun was climbing higher now, burning off the morning mist, revealing the killing ground between their position and the bunker complex.

70 yd of open volcanic ash and rock. Henderson counted four Marine bodies from yesterday’s assault, uncollected because any recovery attempt drew immediate fire from interlocking positions. The battalion had lost 23 men trying to advance this sector in 48 hours. The bunker complex had to be neutralized before the division could push north toward Hill 362A.

Henderson signaled to Corporal Eddie Martinez, positioned 30 yd to their left with a Browning Automatic Rifle. Three short bursts, the prearranged signal. Martinez acknowledged, then opened fire on the bunker’s primary firing port. The sustained BAR fire would force the Japanese gunners back from their position for maybe 10 seconds.

10 seconds for Morrison to aim and fire. “Now!” Henderson shouted. Morrison rose to one knee, the bazooka balanced on his right shoulder, his left hand gripping the wooden forward stock. He aligned the optical sight with the bunker’s dark firing port, visible as a rectangular shadow in the concrete face. His finger found the trigger lever.

The rocket motor ignited with the familiar sharp crack, the backblast kicking up volcanic dust behind them. Henderson watched the rocket streak across the 70 yd, a small contrail marking its path. Standard procedure would have the rocket penetrate the firing port, explode inside, maybe kill one or two defenders if the geometry worked right.

Usually didn’t. This time was different. The warhead impacted just below the firing port at 05:52 and 23 seconds. The explosion seemed smaller than a regular HE round, almost disappointing. Then Henderson saw the white. Pure white fire erupted from the impact point, not like burning gasoline or magnesium flares, but something else entirely.

Brilliant white particles sprayed across the bunker’s face like a horizontal meteor shower, each piece trailing white smoke. Dozens of particles shot through the firing port. Others ricocheted into ventilation slits Henderson hadn’t even known existed. The white particles stuck to concrete, burned into the stone, and kept burning.

5 seconds passed. The bunker’s machine gun fell silent. 10 seconds. White smoke began from every opening in the concrete structure, not gray gunsmoke, but thick white clouds that looked solid enough to walk on. 15 seconds. The screaming started. Henderson had heard men scream before, had heard wounded Marines calling for corpsman, heard Japanese soldiers dying in pillboxes hit with satchel charges.

This was different. These weren’t screams of pain, but of pure animal panic. The sound of men confronting something their training hadn’t prepared them for. 20 seconds after impact, the bunker’s rear entrance, a position so well camouflaged Henderson hadn’t spotted it in 3 days of observation, erupted with Japanese defenders.

Three men stumbled into the open, beating at their uniforms, clawing at burning fragments embedded in their skin and equipment. Their clothes were on fire, but not normal fire. White particles glowed against the dark fabric, each one producing its own column of white smoke. One defender dove face-first into the volcanic ash, trying to smother the flames.

 The burning particles kept glowing through the ash. Martinez’s BAR cut down two defenders before they’d staggered 10 ft from the bunker. The third man, his face obscured by white smoke still rising from burning particles in his hair, ran blindly toward the American lines. He made it 15 yd before a Marine rifleman ended his panic with a single shot.

The white smoke continued pouring from the bunker for another 2 minutes. Henderson could smell it now, a sharp, acrid odor that made his eyes water even at 70 yd. Chemical smoke, not just burning wood or fabric. The machine gun remained silent. No movement came from the firing ports. 5:55 hours. Henderson made the decision.

Martinez, Freeman, on me. We’re checking that bunker. The three Marines crossed the killing ground that had claimed four lives yesterday. Weapons ready, expecting fire from secondary positions. Nothing. They reached the bunker’s blast-scarred face, still radiating heat from the white phosphorus particles embedded in the concrete.

Henderson peered through the firing port, careful not to touch the glowing fragments still burning around the opening’s edge. The interior was hell rendered in white and black. Phosphorus particles had scattered across every surface, burning wherever they’d landed. The machine gun lay abandoned, its barrel bent where someone had tried to drag it away from burning ammunition.

Equipment smoldered. Fabric hung in charred strips. The bunker’s concrete walls channeled white smoke toward the rear exit, but enough particles had fallen to the floor that the defenders would have been wading through burning material with every step. Two bodies lay in the bunker’s main chamber, overcome by smoke before they could escape.

Their uniforms showed dozens of small burn marks where phosphorus particles had embedded and continued burning even after the men died. The white particles were still glowing, still producing smoke, still burning 90 seconds after impact. Henderson had cleared bunkers with satchel charges, with grenades, with point-blank rifle fire.

He’d never seen defenders abandon a position this quickly. Never seen panic override the fanatical defense doctrine that had defined Japanese tactics for 3 years. The white phosphorus hadn’t just killed the defenders or destroyed their position. It had broken their will to fight, driven them into the open where conventional weapons could engage them.

“Jesus Christ,” Martinez whispered, staring at the still burning particles scattered across the bunker floor. “What the hell is that stuff?” Henderson didn’t answer. He was already scanning for the next bunker, the next pillbox, the next impossible defensive position. Morrison still had five M10 rounds in his ammunition bag. They had work to do.

By March 19th, 1945, 2 days after Henderson’s demonstration of the M10’s effectiveness, every Marine bazooka team on Iwo Jima had received white phosphorus rockets. The supply clerks distributed 2,400 rounds in 48 hours, prioritizing units engaged in bunker reduction operations across the northern sectors. The immediate tactical impact was measurable in casualty rates.

Marine divisions equipped with M10 rounds reported 34% fewer casualties during bunker assault operations compared to the previous week’s statistics. The Japanese response revealed genuine fear. Intelligence officers interrogating prisoners captured in late March reported consistent descriptions of the white flame weapon that burned through stone, couldn’t be extinguished, and filled positions with choking smoke.

One prisoner, a sergeant who’d survived an M10 attack on a cave position near Hill 362C, described watching the white particles burn through a wooden support beam in 40 seconds, causing a partial tunnel collapse that buried three defenders. The psychological impact exceeded the physical damage. Defenders who’d held positions under sustained artillery bombardment evacuated after single white phosphorus strikes.

Production limitations prevented unlimited employment. The Chemical Warfare Service facility at Pine Bluff Arsenal, Arkansas, could manufacture approximately 15,000 M10 rounds per month using existing white phosphorus stocks and converted production lines originally designed for chemical smoke shells. This production rate meant field commanders had to carefully allocate the ammunition to priority targets rather than employing it as standard ordnance.

Distribution prioritized Marine Corps units preparing for Operation Downfall, the planned invasion of Japan’s home islands. By June 1945, Marine divisions staged in the Philippines for the Kyushu invasion had received sufficient M10 stocks to equip 1/3 of their bazooka teams with mixed loadouts. Two white phosphorus rounds and four conventional HE rounds per operator.

The tactical doctrine emphasized using M10 rounds as the initial strike against fortified positions followed by conventional assault if the phosphorus attack failed to dislodge defenders. Operational reports from Okinawa, where fighting continued through June 1945, documented the M10’s effectiveness against cave positions that honeycombed the island’s southern limestone ridges.

On May 14th, 1945, Company K, 3rd Battalion, 7th Marines, engaged a cave complex near Shuri Castle that had resisted demolition charges, napalm strikes, and flamethrower assault for 6 days. Three M10 rounds fired into the cave’s main entrance killed or drove out 42 defenders within 8 minutes compared to previous assaults that had caused nine Marine casualties without breaching the position.

The weapon’s limitations became apparent through sustained combat use. White phosphorus particles would occasionally ignite propellant charges in the bazooka tube if moisture contamination allowed premature ignition. Between March and June 1945, 11 Marine bazooka operators suffered burns from misfires, leading to revised handling procedures requiring visual inspection of each round’s waterproof seal before loading.

The rockets proved sensitive to rough handling during amphibious operations. Units landing on Okinawa reported 8% of their M10 stocks arrived with damaged seals, rendering the rounds too hazardous to fire. Enemy countermeasures evolved slowly. By May 1945, Japanese defenders on Okinawa had begun storing water in fortified positions specifically to combat white phosphorus particles based on the mistaken belief that water extinguished the burning material.

This actually worsened casualties. Defenders would immerse burning particles in water buckets, temporarily suppressing the reaction, then suffer renewed burns when the phosphorus reignited upon exposure to air. The tactic’s failure further enhanced the M10’s psychological impact. Defenders concluded the weapon was unstoppable through conventional countermeasures.

Strategic planners preparing for Operation Olympic, the November 1945 invasion of Kyushu, requested 500,000 M10 rounds, enough to equip every Marine and Army bazooka team in the invasion force with sustained white phosphorus capability. Chemical Warfare Service engineers calculated they could meet this requirement by expanding Pine Bluff production and activating secondary facilities with full production reaching 75,000 rounds monthly by September 1945.

The atomic bombings of Hiroshima and Nagasaki on August 6th and 9th, 1945, made these production plans irrelevant. Japan’s surrender on August 15th terminated Operation Downfall and eliminated the need for mass production of specialized anti-fortification ammunition. Pine Bluff Arsenal had manufactured approximately 180,000 M10 rounds by war’s end.

Roughly 35,000 had been expended in combat operations on Iwo Jima and Okinawa. White phosphorus’s chemistry made it uniquely effective against fortified positions while creating handling challenges that required strict protocols. The element exists in several allotropic forms, but the military variant used white phosphorus specifically, a waxy translucent solid that ignites at 86° F and burns until completely oxidized or deprived of oxygen.

The M10 warhead design balanced maximum particle dispersion against reliable detonation. Engineers calculated that 1.3 lb of white phosphorus fragmented into particles ranging from 0.5 g to 5 g would create optimal coverage patterns while ensuring each particle retains sufficient mass to penetrate light cover and continue burning.

The bursting charge, a small explosive positioned at the warhead center, fragmented the metal casing into approximately 400 pieces while simultaneously dispersing the phosphorus in a roughly spherical pattern modified by the rocket’s forward velocity at impact. Field testing revealed that particles smaller than 0.

5 g consumed themselves within 10 seconds while fragments exceeding 10 g tended to embed deeply in targets rather than dispersing across maximum area. The engineers optimized the casing’s scoring pattern to produce the statistically ideal distribution. 60% of particles between 1 to 3 g providing sustained burning without excessive penetration.

The smoke generation created a secondary tactical effect. Each gram of burning white phosphorus produced approximately 3 cubic feet of white smoke per second during active combustion. An M10 detonation inside an enclosed bunker would generate enough smoke to reduce visibility to zero within 20 seconds while simultaneously depleting oxygen levels as the phosphorus consumed available air.

Japanese defenders attempting to maintain defensive positions under these conditions faced a choice between suffocation and evacuation. And evacuating meant exposing themselves to supporting American fire. Operators learned to exploit the weapon’s characteristics through experience. Sergeant Thomas Red Sullivan operating with the Fourth Marine Division on Iwo Jima discovered that firing M10 rounds at the junction between bunker walls and roofs caused particles to bounce downward into the position rather than embedding in

surfaces. This technique shared informally between bazooka teams increased the effective particle dispersion by approximately 25% according to post-combat analysis of struck positions. The rocket’s operational limitations required tactical adaptation. The M10’s maximum effective range was identical to standard bazooka ammunition, 300 yd, but accuracy degraded significantly beyond 150 yd due to the rounds being slightly lighter than HE variants.

Wind conditions affected the rockets more severely than standard ammunition. And operators learned to compensate by aiming 2 to 3° into the wind during shots exceeding 100 yd. Storage problems plagued units operating in tropical environments. The waterproof seals protecting the phosphorus required cool, dry conditions for maximum integrity.

Ammunition stored in landing craft or beach dumps deteriorated rapidly. Marine quartermasters reported that M10 rounds exposed to Pacific humidity for more than 14 days showed a 15% failure rate compared to 2% for freshly delivered ammunition. This led to modified storage procedures requiring M10 stocks to be kept in sealed ammunition carriers with desiccant packets replaced every 72 hours.

Backblast safety required revised positioning protocols. The M10’s rocket motor was identical to standard bazooka rounds, but the psychological impact of firing chemical ammunition made operators more cautious about positioning. Training emphasized maintaining the standard 60-ft backblast clearance. But many operators instinctively increased this distance to 80 or 90 ft when firing phosphorus rounds slightly reducing first shot accuracy due to modified stance and grip.

The Japanese attempted technical analysis of captured M10 rounds but achieved limited success. Intelligence reports from prisoners revealed that Japanese engineers who examined an intact round that failed to detonate correctly identified the phosphorus component but misunderstood the dispersion mechanism. They believed the weapon was designed to create smoke screens for assault operations rather than as an anti-personnel device.

A misapprehension that delayed development of effective countermeasures. Maintenance presented minimal challenges beyond storage concerns. The M10 used the same rocket motor, fins, and electrical ignition system as standard bazooka ammunition requiring no special cleaning or preparation of launchers. Armorers did recommend firing at least one conventional HE round through a bazooka tube after employing M10 ammunition to clear any residual phosphorus particles from the tube’s interior.

Though no documented cases of secondary ignition from contaminated tubes exist in combat records. The M10 white phosphorus bazooka round disappeared from American arsenals almost as quickly as it appeared in combat. Production ceased on August 17th, 1945, 2 days after Japan’s surrender announcement. The Chemical Warfare Service directed Pine Bluff Arsenal to halt all white phosphorus munitions manufacturing and transition production lines back to conventional ordnance by September 1st.

The military classified the M10’s development history, combat employment records, and technical specifications under secret clearance in November 1945. This classification stemmed not from the weapon’s technology white phosphorus had been used in artillery shells since World War I but from sensitivity about chemical warfare perception in the post-war international environment.

The Geneva Protocol of 1925 prohibited chemical weapons use. And while white phosphorus technically qualified as incendiary rather than chemical, military legal advisers worried about perception issues during the war crimes trials proceeding in Tokyo and Nuremberg. Existing stocks faced disposal challenges. The military had accumulated approximately 145,000 unfired M10 rounds by war’s end stored at depots across the Pacific and arsenals in the continental United States.

White phosphorus ammunition requires specialized destruction procedures. Simple burning or conventional demolition can scatter toxic phosphorus particles across wide areas. The Chemical Warfare Service spent 18 months carefully incinerating the stocks in controlled conditions completing disposal operations in March 1947.

The Korean War briefly revived interest in white phosphorus bazooka ammunition. When North Korean forces established fortified positions along the 38th parallel in 1951 Marine Corps Ordnance officers requested access to M10 technical documentation for potential renewed production. The request was denied. The military had transitioned to 3.

5-in M20 Super Bazooka by 1950. And the M10 design was incompatible with the larger diameter tube. Engineers did develop a 3.5-in white phosphorus round designated the M30. But production remained limited and the weapon saw minimal combat employment. Modern white phosphorus munitions evolved from the M10’s basic concept while addressing its limitations.

Current M825 155-mm artillery rounds use felt wedges soaked in white phosphorus rather than simple fragmentation providing more controlled dispersion and extended burn duration. Air Force weapons include the M34 white phosphorus bomb capable of saturating larger areas than rocket-propelled munitions. Naval forces employ white phosphorus in specialized naval gunfire support rounds.

The legal and ethical debates surrounding white phosphorus weapons trace partially to the M10’s combat employment. International humanitarian law currently permits white phosphorus use for illumination and smoke screening, but restricts its deployment against civilian populations or in civilian areas. The protocol on prohibitions or restrictions on the use of incendiary weapons adopted in 1980 addresses white phosphorus indirectly through regulations on incendiary effects rather than chemical composition.

Veterans who employed M10 rounds rarely discussed the weapon publicly. The combination of classification restrictions and the weapon’s brutal effectiveness created a culture of silence around its use. When the classification was reduced to confidential in 1973 then fully declassified in 1991 the surviving operators were in their 60s and 70s and few interviews captured their experiences before they passed.

The weapon’s legacy persists in modern military doctrine emphasizing combined arms approaches to fortified position reduction. The M10 demonstrated that psychological impact could equal or exceed physical destruction in forcing defenders from prepared positions. Current urban warfare tactics incorporate this lesson using thermobaric weapons and white phosphorus rounds to create conditions that make defensive positions untenable rather than attempting to destroy fortifications through brute force.

Staff Sergeant Robert Henderson survived Iwo Jima. He participated in the final northern sector operations employing M10 rounds against cave positions until the island was declared secure on March 26th 1945. His combat record credited him with directing the destruction of 17 fortified positions using white phosphorus ammunition contributing to his Silver Star citation for leadership under fire during the campaign.

Henderson never discussed the M10 rounds publicly. He returned to civilian life in Oregon worked as a machinist and attended veteran reunions where he would speak about fellow Marines but rarely about specific weapons or tactics. When researchers from the Naval Historical Center interviewed him in 1987 for an oral history project Henderson described the white phosphorus rockets as effective and necessary then changed the subject to the men who hadn’t made it home.

PFC James Morrison the young Marine who fired that first M10 round on March 17th received orders transferring him to a replacement battalion preparing for Operation Olympic 3 days after Henderson’s assault. He spent the summer of 1945 training in the Philippines carrying M10 rounds during practice assaults against mock Japanese fortifications preparing for an invasion that never came.

Morrison returned home to Illinois in December 1945 completed college on the GI Bill and became a high school chemistry teacher a career choice he attributed to his wartime experience with the white fire that burned in water. The classification of M10 combat records meant that neither Henderson nor Morrison could discuss their experiences in detail for decades.

The Official Secrets Act they’d signed upon receiving the specialized ammunition remained in effect until 1991 when most records from World War II chemical weapons programs were declassified during a general review of Cold War era secrecy protocols. By the time they could speak freely the technology had evolved beyond recognition.

Modern white phosphorus munitions bear little resemblance to the improvised rocket rounds that terrified Japanese defenders on Iwo Jima. The veterans who employed the M10 understood they’d participated in developing a weapon that changed tactical doctrine even if classification prevented them from sharing those experiences with the public.

The Japanese defenders who faced the white flame and survived carried different memories. In post-war interviews conducted by Allied interrogation teams former soldiers described the M10 attacks as among the most terrifying weapons they’d encountered. Worse than flamethrowers because the burning couldn’t be escaped.

 Worse than artillery because the particles seemed to hunt for gaps in cover. Worse than bombs because the smoke made defensive positions uninhabitable within seconds. One veteran a former Imperial Army Corporal who defended positions on both Iwo Jima and Okinawa told researchers in 1952 “We expected to die. Accepting death made conventional weapons bearable.

But the white flame made us want to live long enough to escape it. That desire to run to breathe to stop burning broke something in men who’d prepared for honorable death. We became animals fleeing fire instead of soldiers defending positions. The men who created deployed and employed the M10 white phosphorus bazooka round developed a weapon that killed through chemistry terror and the simple biological imperative to breathe.

They didn’t celebrate this achievement. They recognized it as necessary within the brutal context of Pacific fortification warfare employed it to save American lives and then with remarkable consistency chose not to speak about it for 50 years. Their silence speaks to the weapon’s effectiveness and the moral weight of using chemistry as a battlefield tool even in the service of ending a war that had already consumed millions of lives.

The Marines who stormed Iwo Jima faced an enemy who had months to prepare defenses and orders to never surrender. The M10 white phosphorus round gave those Marines a fighting chance against positions designed to be their graves. It saved American lives by making Japanese positions untenable not through destruction but through creating conditions where defending meant dying and evacuating meant dying faster.

These stories of forgotten weapons and the men who employed them deserve to be preserved. If this piece of history moved you hit that like button and subscribe so we can keep sharing the innovations sacrifices and impossible victories that shaped the war. Turn on notifications. We’ve got more classified weapons, secret operations and untold stories coming.

Drop a comment letting me know where you’re watching from and if any of your family served in the Pacific theater. These weren’t just weapons. They were tools that brought Marines home alive. The men who created them the operators who fired them and the riflemen they protected earned their place in history. They called it white flame.

The Marines called it survival.